This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived, implemented or described. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
An important aspect of pollution and air constituent detection is an ability to determine the identities of the compounds that are suspected of being the components of the air sample under observation.
One technique to determine the presence of certain compounds in a sample of a gas (e.g., air) is to use spectrometry, spectroscopic techniques and spectroscopic methods. This technique determines the presence and concentration of a given element or compound in a sample via the interaction of energy with the sample. The device that is used is known as a spectrometer or spectrograph. Spectroscopy is a staple of physical or analytical chemistry in the identification of substances through the spectrum emitted from or absorbed by substances that compose the sample.
The data obtained from the use of spectroscopy is referred to as a spectrum. A spectrum is a plot of the intensity of energy detected versus the wavelength (mass, momentum or frequency) of the energy. A spectrum can be used to discover information about the atomic and molecular energy levels, molecular geometry, chemical bonds, the interaction of molecules and related processes. The spectrum can be used to identify (qualitative analysis) the components of a sample. The spectrum can also be used to determine the amount of material (quantitative analysis) in a sample.
A spectroscope typically includes an energy source (commonly a laser) and a device for measuring the change in the energy emitted from the source after it has interacted with the sample. Conversely the sample may be induced to emit light, thereby negating the need for an external light source. The detection portion of the spectroscope is referred to typically as a spectrophotometer.
Mobile devices have been used to aid in the collection data regarding airborne substances, such as those typically associated with sources of pollution. This type of collection basically includes three major steps: (a) collect a sample, (b) determine an interaction of the sample with an energy source, and (c) transmit the result to a server for data analysis. Collection is not particularly difficult as the gases or particles being studied are airborne. Transmission of the result data to the server by the mobile device is also straightforward, as the transmission can occur using standardized wireless (e.g., cellular) interfaces. However, the second step (determination of the sample properties) presents a significant problem.
The most straight forward method would be to employ spectroscopic examination. However, currently available spectroscopes are bulky, sensitive and not designed for use in the field. There are smaller versions available, such as alpha particle or accelerated proton spectrographs, but these devices tend to be expensive and operate using undesirable radiation.